INVESTIGATION OF THE MACHINABILITY OF PEEK, PP AND PTFE HIGH PERFORMANCE ENGINEERING THERMOPLASTICS FOLLOWING HEAT TREATMENT

Abstract

This study investigates the machinability of heat-treated engineering thermoplastics, focusing on Polyetheretherketone (PEEK), Polypropylene (PP), and PolyTetraFluoroEthylene (PTFE), widely used in industry. The materials were annealed at various temperatures, holding times, and cooling rates in an industrial furnace. Heat-treated and non-heat-treated specimens were compared for dimensional accuracy and hardness. Machining, including both milling and drilling operations, was performed on a 5-axis HAAS UMC 750 CNC machine using different cutting tools and machining parameters. Results showed that heat treatment improved dimensional accuracy, especially in PEEK and PTFE, and increased hardness by 7%, 6%, and 11% for PEEK, PP, and PTFE, respectively. Surface roughness decreased, enhancing the surface quality of machined parts. Significant changes in chip morphology, including thickness, color, and length, were observed in heat-treated specimens. These findings demonstrate the beneficial effects of heat treatment on the machinability and mechanical properties of thermoplastics, offering valuable insights for industrial applications.

Keywords

• Polyethereterketone
• Polypropylene
• Polytetrafluoroethylene
• Heat Treatment
• Machinability

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